initial version of mupdf
MuPDF is a lightweight PDF, XPS, and E-book viewer.
It contains a GL version, a X11 version and a CLI mutool.
Test Plan: mupdf has been my default pdf viewer for several months.
Reviewers: Triage Team, JoshStrobl
Reviewed By: Triage Team, JoshStrobl
Maniphest Tasks: T2156
Differential Revision: https://dev.getsol.us/D8143